Created attachment 184 [details]
A picture of ut71c taking measures from 100nF cap and sigrok output

Overview:
--------
there seems to be some issue with measures received from the uni-t ut71c multimeter. 
Say the multimeter is set to measure capacity (C) and the cap is 22uF.
$ sigrok-cli --version
sigrok-cli 0.6.0-git-1ef118a
Using libsigrok 0.4.0-git-e5ef649 (lib version 2:0:0).
Using libsigrokdecode 0.4.0-git-c63f5a8 (lib version 2:0:0).
...

$sigrok-cli --driver=uni-t-ut71c:conn=1a86.e008 --continuous
...
P1: 0.000021 

Increased level of logging:
$sigrok-cli --driver=uni-t-ut71c:conn=1a86.e008 --continuous -l 4  
sr: [00:19.679655] uni-t-dmm: DMM packet:   32 31 31 39 38 34 35 30 31 0d 0a 00 00 00
sr: [00:19.679714] ut71x: Applying factor 0.000000, new value is 0.000021.

The captured frame can be decoded into:
display: 2 1 1 9 8 
range: 4 (40uF)
function: 5
ac/dc: 0 
auto: 1 (auto) 
end of frame: \r \n

I suspect that the the 'factor' strips most of the data leaving 0.000021. 
However, In case of 100nF ceramic cap (marking 104), I got:
$sigrok-cli --driver=uni-t-ut71c:conn=1a86.e008 --continuous
...
P1: 0.000000

Increasing the logging level:
$sigrok-cli --driver=uni-t-ut71c:conn=1a86.e008 --continuous -l 4  
 
...
cli: Received SR_DF_ANALOG (1 samples).
P1: 0.000000 F AUTO
sr: [01:26.748079] uni-t-dmm: DMM packet:   31 31 32 36 32 32 35 30 31 0d 0a 00 00 00
sr: [01:26.748108] ut71x: Applying factor 0.000000, new value is 0.000000.
sr: [01:26.748121] session: bus: Received SR_DF_ANALOG packet (1 samples).

The captured frame can be decoded into:
display: 1 1 2 6 2 
range: 2 (400nF)
function: 5 (C)
ac/dc: 0 
auto: 1 (auto) 
end of frame: \r \n

In this case, it seems that the 'factor' dropped the reading down to 0, which is not quite true. I have compiled all the libs from the source.

Steps to Reproduce
------------------
Set the meter to measure capacitance, auto-range, connect to pc, enter send mode; connect 100nF ceramic cap and measure

Actual Results 
---------------
P1: 0.000000 F AUTO

Expected Results
----------------
Results as sent by the meter

Build Version
-------------
$ sigrok-cli --version
sigrok-cli 0.6.0-git-1ef118a
Using libsigrok 0.4.0-git-e5ef649 (lib version 2:0:0).
Using libsigrokdecode 0.4.0-git-c63f5a8 (lib version 2:0:0).


Regards,
Arek